Patent EA-003601-B1 (EA)
Title: Electrical energy meter
Inventor: BOKMAN MARK
IPC: G07F7/00
Filed: 2000-06-08
Abstract: 1. An electrical energy meter cutting off power supply after a preset (pre-paid) amount has been used up, comprising: -sensors of the electric current parameters changing in time and relays for disconnection the customers from the power network, -reader of information off the smart card about the sum of pre-payment made by the customer for use of electricity, -display for outputting information, -interface to transmit information to external device upon request, -processor to integrate said functional elements of the meter into a system to calculate the amount of expended electricity, pre-payments made by the customers and available credit of each customer, and to control said functional elements of the meter, characterized in that -contains additionally (n-1) sensors of the electric current parameters and (n-1) relays for disconnection the customers from the power network, -multiplexer connected to the outputs of sensors of the current parameters, the output of said multiplexer being coupled with processor to transmit to said processor information about the parameters of the current used by each customer as a function of time, -command unit connected to said processor's outputs to transmit processor's command to the relay of corresponding customer for disconnecting said customer from the power network if the amount of electricity used up by said customer reaches the preset value. - reader of information being made with the possibilities of fixing from smart card of each customer of pre-payments made by the customers. 2. The meter, according to Claim 1, wherein -said sensor of the current parameters is equipped with current transformer, and analog-to-digital -converter is switched on between said multiplexer and said processor, said converter is switched on at intervals of time sufficient to ensure the preset class of accuracy in recording current parameters in time. 3. The meter according to Claim 1, wherein -said sensor of the current parameters is equipped with current transformer, linear pulser and pulse counter, and -said pulse counter is coupled with said processor via multiplexer. 4. The meter according to Claim 1, wherein -said sensor of the current parameters is equipped with current shunt coupled with said linear pulser, -the output of said linear pulser is coupled with said pulse counter via optical circuit separator, -output of said pulse counter is coupled with said processor via said multiplexer, with greater operation safety ensured. 5. The meter according to Claim 1, wherein -functional elements are installed in a single cabinet, -said cabinet is connected by separate cables to the customer's premises controlled individually with prevention of the attempts of unauthorized connections to the power network and/or tampering with the meter's components. 6. The meter according to Claim 1 wherein, in the case of customers being spaced at a substantial distance from each other -is made with placement in the central cabinet and personal cabinets for each customer, -whereas the components serving all customers and transmitter receiver are installed in the central cabinet, and -said personal cabinets are located close to each customer in a place difficult to access, while said personal cabinets house said sensors of current parameters, relays and devices to ensure coupling between personal and central cabinets. 7. The meter according to Claim 6, wherein -the sensor of current parameters is placed in the main cabinet at the meter's input, and -said meter has a device to give an alarm signal and cut off the customer supply if the difference between the amount of electrical energy which has entered the meter and the amount of electrical energy fixed by the sensors of the personal cabinets over the same period of time exceeds the permissible value. 8. The meter according to Claim 5 or 6, wherein its cabinet (cabinets) is/are equipped with a device (devices) for giving a sound signal, disconnecting the customer from the power network and transmitting the alarm signal to electricity supplier if an unauthorized opening of a cabinet (tampering with cabinets) in which the meter is housed (or unauthorized cutting into a section of the power network controlled by the meter) has taken place. 9. Method of preventing excessive energy losses when the meter according to Claim 6 is employed and the following operations are performed in accordance with this method: -measuring the amount of electrical energy which entered the meter over a fixed period of time, -determining the total amount of energy fixed by the sensors in the personal cabinets over the same period of time, -determining real losses (the difference of the amount of electrical energy which entered the meter over some interval of time and the total amount of energy fixed by sensors in personal cabinets over the same interval of time), -comparing the determined real losses with the level of permissible losses, -disconnecting the consumers and giving an alarm signals if real losses exceed the permissible value.